System and method for cleaning sensors of autonomous vehicles

Abstract

An AV sensor can be cleaned by charging a conductive layer over a sensor surface. The conductive layer may be positively or negatively charged and can repel contaminants having the same polarity away from the sensor. The charging of the conductive layer can be triggered by a determination that the sensor needs cleaning, which can be based on sensor data captured by the sensor or a different sensor. The charging of the conductive layer may include one or more charging cycles, each of which includes charging the conductive layer with two opposing polarities. Another conductive layer may be over the conductive layer. The other conductive layer can be charged with an opposite polarity from the conductive layer so that an electric field is present between the two conductive layers. A piezoelectric layer between the two conductive layers can vibrate under the electric field. The vibration can enhance the cleaning.

What is claimed is: 
     
         1 . A method for cleaning a sensor of a vehicle, comprising:
 detecting an electrical polarity of one or more contaminants in an environment surrounding the sensor;   generating an electrical signal based on the electrical polarity of the one or more contaminants; and   providing the electrical signal to a first conductive layer over at least a portion of a surface of the sensor,   wherein the vehicle is to navigate based on data captured by the sensor; and   wherein the vehicle includes an assembly for cleaning the sensor, comprising:
 a controller in communication with the sensor, the controller being configured to navigate the vehicle at least in part based on data received from the sensor; and 
 wherein the assembly includes:
 the first conductive layer over at least a portion of the sensor and a second conductive layer over at least the portion of the sensor; 
 a polarity sensing circuit to determine an electrical polarity of one or more contaminants in an environment surrounding the sensor; 
 a charging circuit to provide electrical charges of the electrical polarity to the first conductive layer and to the second conductive layer, where a charge provided to the first conductive layer has an opposite polarity of a charge provided to the second conductive layer thereby forming an electric field between the two conductive layers, 
 wherein the first conductive layer is configured to repel the one or more contaminants away from the sensor; and 
 
 a piezoelectric layer between the first conductive layer and the second conductive layer, wherein the electric field causes the piezoelectric layer to vibrate. 
   
     
     
         2 . The method of  claim 1 , wherein a polarity of the electrical signal is the same as the polarity of the one or more contaminants. 
     
     
         3 . The method of  claim 1 , wherein:
 the electrical signal has two polarities,   a first polarity of the two polarities is the same as the electrical polarity of the one or more contaminants, and   a second polarity of two polarities is the same as the electrical polarity of the one or more contaminants.   
     
     
         4 . The method of  claim 1 , wherein the conductive layer is a first conductive layer, the electrical signal is a first electrical signal, and the method further comprising:
 generating a second electrical signal; and   providing the second electrical signal to a second conductive layer over the surface of the sensor,   wherein a piezoelectric layer is between the first conductive layer and the second conductive layer.   
     
     
         5 . The method of  claim 4 , further comprising:
 increasing a temperature of the piezoelectric layer.   
     
     
         6 . The method of  claim 4 , wherein the piezoelectric layer has an opening over at least a portion of the first conductive layer. 
     
     
         7 . The method of  claim 1 , further comprising:
 determining that the surface of the sensor needs cleaning based on sensor data capturing the one or more contaminants.   
     
     
         8 . The method of  claim 1 , wherein:
 the conductive layer is a conductive layer in an array of conductive layers,   different conductive layers in the array are over different portions of the surface of the sensor, and   the conductive layers in the array are electrically insulated from each other.   
     
     
         9 . The method of  claim 8 , further comprising:
 providing a sequence of electrical signals to the conductive layers in the array,   wherein each respective electrical signal in the sequence is provided to a different conductive layer in the array at a different time.   
     
     
         10 . The method of  claim 9 , further comprising:
 determining the sequence based on locations of the conductive layers in the array.   
     
     
         11 . A vehicle including a sensor and an assembly for cleaning the sensor, comprising:
 a sensor;   a controller in communication with the sensor, the controller being configured to navigate the vehicle at least in part based on data received from the sensor; and   an assembly for cleaning the sensor, wherein the assembly includes:
 a first conductive layer over at least a portion of the sensor and a second conductive layer over at least the portion of the sensor; 
 a polarity sensing circuit to determine an electrical polarity of one or more contaminants in an environment surrounding the sensor; 
 a charging circuit to provide electrical charges of the electrical polarity to the first conductive layer and to the second conductive layer, where a charge provided to the first conductive layer has an opposite polarity of a charge provided to the second conductive layer thereby forming an electric field between the two conductive layers, 
 wherein the first conductive layer is configured to repel the one or more contaminants away from the sensor, and the vehicle is to navigate based on data; and 
 a second conductive layer over at least the portion of the sensor; and 
 a piezoelectric layer between the first conductive layer and the second conductive layer, wherein the electric field causes the piezoelectric layer to vibrate. 
   
     
     
         12 . The vehicle of  claim 11 , further comprising:
 a contaminant detector to detect the one or more contaminants.   
     
     
         13 . The vehicle of  claim 11 , further comprising:
 a heating circuit to increase a temperature of the piezoelectric layer.   
     
     
         14 . The vehicle of  claim 11 , wherein the piezoelectric layer includes an opening over an aperture of the sensor. 
     
     
         15 . The vehicle of  claim 11 , wherein the charging circuit comprises a power supply having a positive terminal and a negative terminal, and wherein the power supply supplies the electrical charges to the conductive layer. 
     
     
         16 . The vehicle of  claim 15 , wherein a voltage difference between a voltage of the positive terminal and a voltage of the negative terminal is a first electrical voltage, and the charging circuit further comprises a charge pump coupled to the power supply, the charge pump being configured and to generate a second electrical voltage that is different from the first electrical voltage. 
     
     
         17 . The vehicle of  claim 11 , wherein the piezoelectric layer includes a plurality of piezoelectric elements electrically insulated from each other.